Thailand, Laos, Cambodia, and Vietnam have all but abandoned the 1995 Mekong agreement to pursue hydro deals that threaten the river’s highly productive fisheries and millions of people who depend upon those resources.

Under the Mekong agreement, governments are obliged to “make every effort to avoid, minimize and mitigate harmful effects” that development projects might cause to the aquatic ecosystem and ecological balance of the river system.

Instead, state power utilities have dammed every major Mekong tributary for hydropower, blocking movement of the Mekong’s migratory fish populations, and depriving riparian communities of a vital source of food and income. The Mekong River Commission, for its part, has paid scant attention to the cumulative impacts of these dams on fisheries and people’s food security, despite its obligations under the Mekong agreement.

Now the mainstream Mekong is at risk: Laos and Cambodia have struck deals with Chinese, Malaysian, and Thai companies to update plans for as many as six hydro dams across the lower Mekong.

MRC scientists have warned that any dams on the mainstream could be disastrous for Mekong fisheries, particularly in Cambodia where the fishing industry generates one-tenth of the country’s GDP, if not more.

But Mekong governments see only megawatts and the revenue big dams can generate for state coffers. Unconstrained, Mekong utilities will try to maximize the value of power from their dams by storing water overnight when electricity demand is low, and then releasing water through the turbines during daily periods of peak demand.

This type of peak-flow operation wreaks havoc on migratory fish species and seasonal agriculture, as people living downstream from Electricity of Vietnam’s dams on the Se San River can attest.

Contrast this with the United States, where federal legislation has effectively outlawed destructive peaking operations in a number of jurisdictions. Hundreds of hydro projects up for relicensing by the Federal Energy Regulatory Commission (FERC) have been instructed to balance hydropower production with environmental requirements. This has often meant switching from peaking mode to run-of-river flows, where releases from the dam equal water flows into the reservoir throughout the year.

In Michigan, for example, the Consumers Energy Company was ordered to switch to run-of-river flows at two of its hydro dams on the Manistee River, after 70 years of peak-flow operations. By lowering water temperature and increasing substrate in the riverbed, the company’s switch to run-of-river flows dramatically increased the number of Chinook salmon migrating from the river into Lake Michigan – from below 100,000 to nearly 400,000 fish per year.

By releasing water from dams at the right time and in the right quantity to mimic the river’s natural flow regime, downstream habitat can be recreated and other ecological functions restored – without drastic reductions in annual power output. Biologists are now beginning to document such benefits from dam modifications in Maine, Tennessee, California, and elsewhere.

Provincial regulators in Canada have instructed British Columbia Hydro to stop some of its peaking operations during fish spawning seasons, with the expectation that this will improve fish habitat and water quality downstream. Regulators also instructed the utility to develop a new set of operating rules for its 30 hydro facilities based on consultations with local residents, fisheries associations, business operators, and relevant government agencies.

Not all rivers can be restored by simply adjusting hydro operations. In some cases, dam removal will be the only sensible option. But for now, legislation that imposes environmental constraints on hydro operations, and forces dam owners to recognize the priorities of other water users, is changing the way rivers are managed for the better.

Reclaiming the Mekong from dam building monopolists requires an equally bold approach. Legislation and regulations governing Mekong dam builders are needed within each national jurisdiction. Such legislation must empower government regulators and enforce hydro licensing procedures. The aim should be balancing power production objectives with equally legitimate public demands for fisheries and water quality protection.

If Mekong dam builders stay unlicensed and poorly regulated, they will continue to lag behind their global counterparts on river management, proposing unwanted hydro dams in the wrong places, on the wrong scale, and at the expense of other resource users and the big river itself.

Lawmakers must act now to save the Mekong.

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Grainne Ryder is the Policy Director of Toronto-based Probe
International, a citizens group monitoring power sector aid and reform in the six-country Mekong region. She can be reached at grainneryder@probeinternational.org